摘要
文章针对某采用双侧壁导洞法施工的大跨隧道在导洞施工过程中的临时支护破坏现象,结合实际的净空收敛监控数据对支护内力进行了反分析,重点就支护破坏形成原因进行了分析。分析结果表明:当导洞下台阶开挖时,导洞内壁会产生较大的水平变形,且后续导洞开挖对先开挖侧导洞临时支护变形影响较大;下台阶位置处临时支护以承受弯曲应力为主,受力状态较为不利,易因弯曲应力过大而导致拉裂破坏;先行开挖侧导洞临时支护在后开挖侧导洞施工的反复影响下,无论是轴向应变还是弯曲应变均明显高于后开挖侧导洞,破坏程度因此也更为严重。
Back-analysis was conducted to determine internal tunnel forces causing support failures of a large-span railway station tunnel excavated by double-side heading method on the basis of measured horizontal convergence movements.Results demonstrated that excessive local deformations of the diaphragm walls at the lower bench level occurred and the subsequent heading excavation greatly affected the temporary support structure.The temporary support structure at the lower bench sustained large bending stresses,which resulted in cracking failure.Both the axial and bending strains of the previous temporary support were larger than that of the later ones due to repeated effects of subsequent construction,and the failures were more serious.
出处
《现代隧道技术》
EI
北大核心
2011年第4期92-96,共5页
Modern Tunnelling Technology
关键词
大跨隧道
双侧壁导洞法
支护破坏
原因分析
Tunnels
Double-side heading method
Support failure
Cause analysis
